Process using an integrated coalescing system for separating dispersed ionic liquid from liquid hydrocarbon

ABSTRACT

A process is provided for separating an ionic liquid from a liquid hydrocarbon, using an integrated coalescing system. The integrated coalescing system for separating ionic liquid from a liquid hydrocarbon may comprise:
     a. a bulk settler,   that separates an emulsion comprising the dispersed ionic liquid with a wide range of droplet sizes into a clean ionic liquid phase and a separated liquid hydrocarbon phase comprising retained droplets;   b. a pre-coalescer that receives the separated liquid hydrocarbon phase, separates out solid particles from the separated liquid hydrocarbon phase, and begins to form coalesced droplets of the retained droplets; and   c. a coalescer that receives an effluent from the pre-coalescer, wherein the at least one coalescer comprises multiple layers of media having a fine pore size, and produces a clean hydrocarbon stream that is essentially free of the dispersed ionic liquid and additional amounts of the clean ionic liquid phase.

This application is a divisional of U.S. patent application Ser. No.15/251,640, published as US201800562123A1, filed Aug. 30, 2016, now U.S.Pat. No. 9,956,504; and herein incorporated in its entirety.

TECHNICAL FIELD

This application is directed to improved systems and processes forseparating dispersed ionic liquids from liquid hydrocarbons.

SUMMARY

This application provides an integrated coalescing system for separatinga dispersed ionic liquid from a liquid hydrocarbon, comprising:

a. at least one bulk settler,

that receives an emulsion comprising the dispersed ionic liquid with awide range of droplet sizes ranging from small droplets less than 20microns to large droplets greater than 500 microns, and

that separates the emulsion into a clean ionic liquid phase, that isessentially free of the liquid hydrocarbon, and into a separated liquidhydrocarbon phase comprising retained ionic liquid droplets;

b. at least one pre-coalescer connected to the at least one bulk settlerthat receives the separated liquid hydrocarbon phase, separates outsolid particles from the separated liquid hydrocarbon phase, and beginsto form coalesced droplets of the retained ionic liquid droplets; and

c. at least one coalescer that is fluidly connected to the at least onepre-coalescer and receives an effluent from the at least onepre-coalescer, wherein the at least one coalescer comprises multiplelayers of media having a fine pore size of 20 microns or less, andproduces a clean hydrocarbon stream that is essentially free of thedispersed ionic liquid and additional amounts of the clean ionic liquidphase.

This application also provides a process for separating an ionic liquidfrom a liquid hydrocarbon, comprising:

a. settling an emulsion of the ionic liquid and the liquid hydrocarbon,wherein the emulsion comprises a dispersed ionic liquid with a widerange of droplet sizes, ranging from small droplets less than 20 micronsto large droplets greater than 500 microns, to separate a clean ionicliquid phase that is free of the liquid hydrocarbon from a separatedliquid hydrocarbon phase comprising retained ionic liquid droplets;

b. pre-coalescing the separated liquid hydrocarbon phase in at least onepre-coalescer that removes any particles and begins to form coalesceddroplets of the dispersed ionic liquid;

c. coalescing an effluent from the at least one pre-coalescer in atleast one coalescer comprising multiple layers of media having a finepore size of 20 microns or less to produce a clean hydrocarbon streamthat is essentially free of the dispersed ionic liquid and producesadditional amounts of the clean ionic liquid phase.

The present invention may suitably comprise, consist of, or consistessentially of, the elements in the claims, as described herein.

GLOSSARY

“Dispersed” refers to a distribution (as fine droplets) more or lessevenly throughout a medium.

“Ionic Liquid” refers to materials consisting entirely of ions that is asalt in which the ions are poorly coordinated, which results in the saltbeing liquid below 100° C., or even at room temperature

“Acidic ionic liquid” refers to ionic liquids consisting entirely ofions, that can donate a proton or accept an electron pair in reactions,and that are liquid below 100° C.

“Emulsion” refers to a colloid of two or more immiscible liquids whereone liquid contains a dispersion of the other liquids. In the context ofthis disclosure the ionic liquid will form droplets and dispersethroughout a hydrocarbon.

“Liquid” refers to a phase of matter in which atoms or molecules canmove freely while remaining in contact with one another. A liquid takesthe shape of its container, and is unlike a gas or a solid.

“Bulk settler” refers to an apparatus that separates a dispersed phasefrom an emulsion using the different density of the liquids beingseparated.

“Predominantly” refers to greater than 50 wt %, such as from greaterthan 50 wt % up to 100 wt %, in the context of this disclosure.

“Essentially” refers to from 90 wt % to 100 wt % in the context of thisdisclosure.

“Periodic Table” refers to the version of the IUPAC Periodic Table ofthe Elements dated Jun. 22, 2007, and the numbering scheme for thePeriodic Table Groups is as described in Chemical And Engineering News,63(5), 27 (1985).

“Hydrophilic” refers to a property of a substance to have a tendency tomix with, dissolve in, or be wetted by water.

“Hydrophobic” refers to a property of a substance to repel water.Hydrophobic molecules tend to be nonpolar molecules and group together.

“Fiberglass” is a type of fiber-reinforced plastic where thereinforcement fiber is specifically glass fiber. In the context of thisdisclosure, fiberglass refers to the complete glass-fiber-reinforcedcomposite material, rather than only to the glass fiber within it.

“Turbidity” is the cloudiness or haziness of a fluid caused by largenumbers of individual particles or droplets that are generally invisibleto the naked eye. Turbidity can be measured with an instrument called anephelometer, with a detector set up to the side of a light beam. Morelight reaches the detector if there are lots of small dropletsscattering the source beam than if there are few. The units of turbidityfrom a calibrated nephelometer are called Nephelometric Turbidity Units(NTU).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an experimental cold flow unit used to measuredroplet sizes.

FIG. 2 is a graph of the droplet size distribution in a stable ionicliquid-heptane emulsion comprising 10 vol % ionic liquid.

FIG. 3 is a graph of the droplet size distribution in a stable ionicliquid-heptane emulsion comprising 1 vol % ionic liquid.

FIG. 4 is a diagram of a second experimental cold flow unit with apre-coalescer and a coalescer that was used to assess the effectivenessof the separating process and to measure droplet sizes.

FIG. 5 is a diagram of a third experimental cold flow unit with apre-coalescer and a coalescer comprising fiberglass media having a finepore size.

FIG. 6 is a schematic diagram of a pilot plant with an integratedcoalescing system for separating an ionic liquid from a liquidhydrocarbon.

FIG. 7 is a diagram of an alternative integrated coalescing system forseparating an ionic liquid from a liquid hydrocarbon.

DETAILED DESCRIPTION

Bulk Settler

The bulk settler receives the emulsion comprising the dispersed ionicliquid and separates the emulsion into a clean ionic liquid phase and aseparated liquid hydrocarbon phase comprising retained ionic liquiddroplets. Examples of bulk settlers include: centrifuges, gravitysettlers, membrane-assisted settlers, impingement separators, inclinedplate settlers, scroll centrifuges, settler tanks, and cycloneseparators.

In one embodiment, the bulk settler uses gravity to separate theemulsion. In one embodiment, to enhance its performance, the bulksettler may comprise one or more coarse coalescing pads, such asstructured packing, parallel plates or knitted mesh, which can be madefrom metal or nonmetallic materials that are compatible with theemulsion.

In one embodiment, the bulk settler is configured to predominantly, butnot completely, separate the dispersed ionic liquid from the emulsion.In one embodiment, the emulsion remains in the bulk settler for 0.10 to10 hours.

In one embodiment, the bulk settler is sized to accept from greater than50 vol % to 100 vol % of the effluent from a hydrocarbon conversionreactor that forms the emulsion. In another embodiment, the bulk settleris sized to receive all, or essentially all, of the effluent from thehydrocarbon conversion reactor that forms the emulsion.

In one embodiment, the bulk settler is fluidly connected to ahydrocarbon conversion reactor that produces the emulsion, and the cleanionic liquid phase is fed to an inlet of the hydrocarbon conversion.This embodiment is shown in FIG. 6.

The settling step, such as in the bulk settler, separates the emulsioninto a clean ionic liquid phase that is essentially free of the liquidhydrocarbon. By “essentially free of the liquid hydrocarbon” refers to acondition wherein the clean ionic liquid phase contains no hydrocarbondroplets, however, the clean ionic liquid phase may still contain smallamounts of hydrocarbon that is completely dissolved in the clean ionicliquid phase. The small amounts of the liquid hydrocarbon that can bedissolved in the clean ionic liquid can be from zero to 5 wt %. Anyhydrocarbon that is dissolved into the clean ionic liquid phase will notbe separated out by the settling and coalescing.

In one embodiment, the clean ionic liquid phase may retain less than 5wt % of the liquid hydrocarbon that has dissolved into the ionic liquidphase.

The clean ionic liquid phase can be sent to an ionic liquid reservoir,or a portion thereof can be sent to a regeneration apparatus. The cleanionic liquid phase can be suitable for use in a hydrocarbon conversionreactor. This clean ionic liquid phase can be combined with anadditional ionic liquid phase produced in the coalescer and they can becirculated together to the hydrocarbon conversion reactor.

Hydrocarbon Conversion Reactor

Examples of hydrocarbon conversion reactors include continuously stirredtank reactors, fixed bed reactors, nozzles, motionless mixers, andpressure vessels. Examples of hydrocarbon conversion processes performedin the hydrocarbon conversion reactor include paraffin alkylation,olefin dimerization, olefin oligomerization, concurrent alkylation andoligomerization, isomerization, and aromatic alkylation. In oneembodiment, the hydrocarbon conversion reactor can make gasoline, middledistillate, base oil, or petrochemical components.

In one embodiment, the hydrocarbon conversion reactor makes theemulsion. In one embodiment the hydrocarbon conversion reactor is anozzle reactor comprising one or more Venturi nozzles. In anotherembodiment, the hydrocarbon conversion reactor comprises one or morehigh shear mixers.

Emulsion

The emulsion comprises a dispersed ionic liquid phase in a hydrocarboncontinuous phase. The emulsion comprising the dispersed ionic liquid hasa wide range of droplet sizes, ranging from small droplets less than 20microns to large droplets greater than 500 microns. Examples of dropletsize distributions that can be used include those shown in FIGS. 2 and3, which have droplet size distributions from less than 1 micron up toabout 1000 microns.

In one embodiment, the emulsion comprises the small droplets of theionic liquid that are less than 10 microns. The emulsion comprises thedispersed ionic liquid in a liquid hydrocarbon. In one embodiment, theliquid hydrocarbon is a liquid at ambient temperature and pressure. Inone embodiment the liquid hydrocarbon may comprise one or more of analkylate gasoline, a base oil, a middle distillate, or a chemicalintermediate.

In one embodiment, the emulsion contains 1-30 vol % of the dispersedionic liquid. In another embodiment, the emulsion contains 1-10 vol % ofthe dispersed ionic liquid. In another further embodiment, the emulsioncontains 1-3 vol % of the dispersed ionic liquid.

In one embodiment, the emulsion is produced by feeding a hydrocarbon andan ionic liquid separately into one or more Venturi nozzles. In theVenturi nozzles, the ionic liquid is mixed intimately with thehydrocarbon and is dispersed into fine droplets. In another embodiment,the emulsion is produced by mixers, such as high shear mixers.

Acidic Ionic Liquid

In one embodiment, the dispersed ionic liquid is an acidic ionic liquid.Examples of acidic ionic liquid catalysts and their use for alkylationof paraffins with olefins are taught, for example, in U.S. Pat. Nos.7,432,408 and 7,432,409, 7,285,698, and U.S. patent application Ser. No.12/184,069, filed Jul. 31, 2008. In one embodiment, the acidic ionicliquid is a composite ionic liquid catalyst, wherein the cations comefrom a hydrohalide of an alkyl-containing amine or pyridine, and theanions are composite coordinate anions coming from two or more metalcompounds.

The most common acidic ionic liquids are those prepared fromorganic-based cations and inorganic or organic anions. The acidic ionicliquid is composed of at least two components which form a complex. Theacidic ionic liquid comprises a first component and a second component.The first component of the acidic ionic liquid will typically comprise aLewis acid compound selected from components such as Lewis acidcompounds of Group 13 metals, including aluminum halides, alkyl aluminumdihalides, gallium halide, and alkyl gallium halide (see the PeriodicTable, which defines the elements that are Group 13 metals). Other Lewisacid compounds besides those of Group 13 metals may also be used. In oneembodiment the first component is aluminum halide or alkyl aluminumdihalide. For example, aluminum trichloride (AlCl₃) may be used as thefirst component for preparing the ionic liquid catalyst. In oneembodiment, the alkyl aluminum dihalides that can be used can have thegeneral formula Al₂X₄R₂, where each X represents a halogen, selected forexample from chlorine and bromine, each R represents a hydrocarbyl groupcomprising 1 to 12 atoms of carbon, aromatic or aliphatic, with abranched or a linear chain. Examples of alkyl aluminum dihalides includedichloromethylaluminum, dibromomethylaluminum, dichloroethylaluminum,dibromoethylaluminum, dichloro n-hexylaluminum,dichloroisobutylaluminum, either used separately or combined.

The second component making up the acidic ionic liquid can be an organicsalt or mixture of salts. These salts may be characterized by thegeneral formula Q+A−, wherein Q+ is an ammonium, phosphonium, boronium,oxonium, iodonium, or sulfonium cation and A− is a negatively chargedion such as Cl⁻, Br⁻, ClO₄ ⁻, NO₃ ⁻, BF₄ ⁻, BCl₄ ⁻, PF₆ ⁻, SbF₆ ⁻, AlCl₄⁻, Al₂Cl₇ ⁻, Al₃Cl₁₀ ⁻, GaCl₄ ⁻, Ga₂Cl₇ ⁻, Ga₃Cl₁₀ ⁻, AsF₆ ⁻, TaF₆ ⁻,CuCl₂ ⁻, FeCl₃ ⁻, AlBr₄ ⁻, Al₂Br₇ ⁻, Al₃Br₁₀ ⁻, SO₃CF₃ ⁻, and3-sulfurtrioxyphenyl.

In one embodiment the second component is selected from those havingquaternary ammonium halides containing one or more alkyl moieties havingfrom about 1 to about 9 carbon atoms, such as, for example,trimethylammonium hydrochloride, methyltributylammonium, 1-butylpyridinium, or alkyl substituted imidazolium halides, such as forexample, 1-ethyl-3-methyl-imidazolium chloride.

In one embodiment, the acidic ionic liquid comprises a monovalent cationselected from the group consisting of a pyridinium ion, an imidazoliumion, a pyridazinium ion, a pyrazolium ion, an imidazolinium ion, aimidazolidinium ion, an ammonium ion, a phosphonium ion, and mixturesthereof. Examples of possible cations (Q+) include abutylethylimidazolium cation [beim], a butylmethylimidazolium cation[bmim], butyldimethylimidazolium cation [bmmim], decaethylimidazoliumcation [dceim], a decamethylimidazolium cation [dcmim], adiethylimidazolium cation [eeim], dimethylimidazolium cation [mmim], anethyl-2,4-dimethylimidazolium cation [e-2,4-mmim], anethyldimethylimidazolium cation [emmim], an ethylimidazolium cation[eim], an ethylmethylimidazolium [emim] cation, anethylpropylimidazolium cation [epim], an ethoxyethylmethylimidazoliumcation [etO-emim], an ethoxydimethylimidazolium cation [etO-mmim], ahexadecylmethylimidazolium cation [hexadmim], a heptylmethylimidazoliumcation [hpmim], a hexaethylimidazolium cation [hxeim], ahexamethylimidazolium cation [hxmim], a hexadimethylimidazolium cation[hxmmim], a methoxyethylmethylimidazolium cation [meO-emim], amethoxypropylmethylimidazolium cation [meO-prmim], a methylimidazoliumcation [mim], dimethylimidazolium cation [mmim], amethylnonylimidazolium cation [mnim], a methylpropylimidazolium cation[mpim], an octadecylmethylimidazolium cation [octadmim], ahydroxylethylmethylimidazolium cation [OH-emim], ahydroxyloctylmethylimidazolium cation [OH-omim], ahydroxylpropylmethylimidazolium cation [OH-prmim], anoctylmethylimidazolium cation [omim], an octyldimethylimidazolium cation[ommim], a phenylethylmethylimidazolium cation [ph-emim], aphenylmethylimidazolium cation [ph-mim], a phenyldimethylimidazoliumcation [ph-mmim], a pentylmethylimidazolium cation [pnmim], apropylmethylimidazolium cation [prmim], a 1-butyl-2-methylpyridiniumcation[1-b-2-mpy], 1-butyl-3-methylpyridinium cation[1-b-3-mpy], abutylmethylpyridinium [bmpy] cation, a1-butyl-4-dimethylacetylpyridinium cation [1-b-4-DMApy], a 1-butyl-4-35methylpyridinium cation[1-b-4-mpy], a 1-ethyl-2-methylpyridiniumcation[1-e-2-mpy], a 1-ethyl-3-methylpyridinium cation[1-e-3-mpy], a1-ethyl-4-dimethylacetylpyridinium cation[1-e-4-DMApy], a1-ethyl-4-methylpyridinium cation[1-e-4-mpy], a 1-hexyl-54dimethylacetylpyridinium cation[1-hx-4-DMApy], a1-hexyl-4-methylpyridinium cation[1-hx-4-mpy], a1-octyl-3-methylpyridinium cation[1-o-3-mpy], a1-octyl-4-methylpyridinium cation[1-o-4-mp y], a1-propyl-3-methylpyridinium cation[1-pr-3-mpy], a1-propyl-4-methylpyridinium cation[1-pr-4-mpy], a butylpyridinium cation[bpy], an ethylpyridinium cation [epy], a heptylpyridinium cation[hppy], a hexylpyridinium cation [hxpy], a hydroxypropylpyridiniumcation [OH-prpy], an octylpyridinium cation [opy], a pentylpyridiniumcation [pnpy], a propylpyridinium cation [prpy], abutylmethylpyrrolidinium cation [bmpyr], a butylpyrrolidinium cation[bpyr], a hexylmethylpyrrolidinium cation [hxmpyr], a hexylpyrrolidiniumcation [hxpyr], an octylmethylpyrrolidinium cation [ompyr], anoctylpyrrolidinium cation [opyr], a propylmethylpyrrolidinium cation[prmpyr], a butylammonium cation [b-N], a tributylammonium cation[bbb-N], a tetrabutylammonium cation [bbbb-N], abutylethyldimethylammonium cation [bemm-N], a butyltrimethylammoniumcation [bmmm-N], a N,N,N-trimethylethanolammonium cation [choline], anethylammonium cation [e-N], a diethylammonium cation [ee-N], atetraethylammonium cation [eeee-N], a tetraheptylammonium cation[hphphphp-N], a tetrahexylammonium cation [hxhxhxhx-N], a methylammoniumcation [m-N], a dimethylammonium cation [mm-N], a tetramethylammoniumcation [mmmm-N], an ammonium cation [N], a butyldimethylethanolammoniumcation [OHe-bmm-N], a dimethylethanolammonium cation [OHe-mm-N], anethanolammonium cation [OHe—N], an ethyldimethylethanolammonium cation[OHe-emm-N], a tetrapentylammonium cation [pnpnpnpn-N], atetrapropylammonium cation [prprprpr-N], a tetrabutylphosphonium cation[bbbb-P], a tributyloctylphosphonium cation [bbbo-P], or combinationsthereof.

In one embodiment, the second component is selected from those havingquaternary phosphonium halides containing one or more alkyl moietieshaving from 1 to 12 carbon atoms, such as, for example,trialkyphosphonium hydrochloride, tetraalkylphosphonium chlorides, andmethyltrialkyphosphonium halide.

In one embodiment, the acidic ionic liquid comprises an unsubstituted orpartly alkylated ammonium ion.

In one embodiment, the acidic ionic liquid is chloroaluminate or abromoaluminate. In one embodiment the acidic ionic liquid is aquaternary ammonium chloroaluminate ionic liquid having the generalformula RR′ R″ N H+Al₂Cl₇ ⁻, wherein R, R′, and R″ are alkyl groupscontaining 1 to 12 carbons. Examples of quaternary ammoniumchloroaluminate ionic liquids are an N-alkyl-pyridinium chloroaluminate,an N-alkyl-alkylpyridinium chloroaluminate, a pyridinium hydrogenchloroaluminate, an alkyl pyridinium hydrogen chloroaluminate, a dialkyl-imidazolium chloroaluminate, a tetra-alkyl-ammoniumchloroaluminate, a tri-alkyl-ammonium hydrogen chloroaluminate, or amixture thereof.

The presence of the first component should give the acidic ionic liquida Lewis or Franklin acidic character. Generally, the greater the moleratio of the first component to the second component, the greater is theacidity of the acidic ionic liquid.

For example, a typical reaction mixture to prepare n-butyl pyridiniumchloroaluminate ionic liquid is shown below:

In one embodiment, the acidic ionic liquid utilizes a co-catalyst toprovide enhanced or improved alkylation activity. Examples ofco-catalysts include alkyl halide or hydrogen halide. A co-catalyst cancomprise, for example, anhydrous HCl or organic chloride (see, e.g.,U.S. Pat. No. 7,495,144 to Elomari, and U.S. Pat. No. 7,531,707 toHarris et al.). When organic chloride is used as the co-catalyst withthe acidic ionic liquid, HCl may be formed in situ in the apparatuseither during the alkylating or during post-processing of the output ofthe alkylating. In one embodiment, the alkylating with the acidic ionicliquid is conducted in the presence of a hydrogen halide, e.g., HCl.

The alkyl halides that may be used include alkyl bromides, alkylchlorides and alkyl iodides. Such alkyl halides include but are notlimited to isopentyl halides, isobutyl halides, t-butyl halides, n-butylhalides, propyl halides, and ethyl halides. Alkyl chloride versions ofthese alkyl halides can be preferable when chloroaluminate ionic liquidsare used. Other alkyl chlorides or alkyl halides having from 1 to 8carbon atoms can be also used. The alkyl halides may be used alone or incombination.

When used, the alkyl halide or hydrogen halide co-catalysts are used incatalytic amounts. In one embodiment, the amounts of the alkyl halidesor hydrogen halide should be kept at low concentrations and not exceedthe molar concentration of the AlCl₃ in the acidic ionic liquid. Forexample, the amounts of the alkyl halides or hydrogen halide used mayrange from 0.05 mol %-100 mol % of the Lewis acid AlCl₃ in the acidicionic liquid in order to keep the acidity of the acidic ionic liquidcatalyst at the desired performing capacity.

In one embodiment, the acidic alkylation catalyst comprises an ionicliquid catalyst and a Brønsted acid. In this embodiment, the Brønstedacid acts as a promoter or co-catalyst. Examples of Brønsted acids aresulfuric acid, HCl, HBr, HF, phosphoric acid, HI, etc. Other strongacids that are proton donors can also be suitable Brønsted acids. In oneembodiment, the Brønsted acid is produced internally within the processby the conversion of an alkyl halide into the corresponding hydrogenhalide.

Pre-Coalescer

The integrated coalescing system additionally comprises at least onepre-coalescer connected to the at least one bulk settler. Thepre-coalescer receives the separated liquid hydrocarbon phase that stillcomprises retained ionic liquid droplets. The pre-coalescer separatesout solid particles, from the separated liquid hydrocarbon phase, thatcould potentially foul the downstream coalescer. The pre-coalescer alsobegins to form coalesced droplets of the retained ionic liquid droplets.The pre-coalescer can function as a preconditioner and allows moreefficient separation in a subsequent fluidly-connected coalescer. Thepre-coalescing of the separated liquid hydrocarbon phase in the at leastone pre-coalescer can remove solid particles and begin to form coalesceddroplets of the dispersed ionic liquid.

In one embodiment, the pre-coalescer is selected to comprise a mediumwith a pore size smaller than the pore size of the media in thedownstream coalescer, allowing the removal of any solid particles thatcould potentially foul the downstream coalescer. In one embodiment, thesolid particles removed by the pre-coalescer are contaminants in one orboth of the ionic liquid phase and the hydrocarbon phase. Thecontaminants may be one or more of corrosion products, partiallyhydrolyzed ionic liquid, and other contaminants carried from upstreamprocesses. In one embodiment, the solid particles are not particles thatare formed in the hydrocarbon conversion reactor. In one embodiment, noseparated ionic liquid phase is collected from the pre-coalescer. In oneembodiment, the pre-coalescer has one outlet.

In one embodiment, the pre-coalescer has a medium with a pore size lessthan 50 microns, such as from 1 to 25 microns. In one embodiment, thepre-coalescer comprises a medium made from fiber glass, wool, resins,polymers or fine metal mesh. In one embodiment, the medium used in thepre-coalescer is compatible with the separated liquid hydrocarbon phaseand the retained ionic liquid droplets.

In one embodiment, the pre-coalescer comprises a filter. In oneembodiment the filter has a pore size from 2 to 20 microns, such as from3 to 15 microns, or from 5 to 12 microns. The pre-coalescer caneffectively remove solid particles from the separated liquid hydrocarbonphase and prevent fouling of the downstream coalescer, thereforesignificantly extending the life of the downstream coalescer. In oneembodiment, the pre-coalescer is configured to target the removal ofsolid particles that could foul the downstream coalescer. For example,the pre-coalescer can comprise a filter that removes solid particlesgreater than or equal to 1 micron, such as from 1 to 3000 microns,greater than 5 microns, or greater than 10 microns.

In one embodiment, the effluent from the pre-coalescer is passeddirectly through the outlet of the pre-coalescer into an inlet of acoalescer that is fluidly connected to the pre-coalescer.

Coalescer

The integrated coalescing system additionally comprises at least onecoalescer that is fluidly connected to the at least one pre-coalescer.The coalescer receives an effluent from the pre-coalescer. The coalescercomprises multiple layers of media having a fine pore size of 20 micronsor less. The coalescer produces both a clean hydrocarbon stream that isessentially free of the dispersed ionic liquid and also additionalamounts of the clean ionic liquid phase.

In one embodiment, the multiple layers of media can be arranged to havealternating hydrophilic surface properties and hydrophobic surfaceproperties. Examples of media having hydrophilic surface propertiesinclude various metals, including metal alloys. In one embodiment, themetal media provides structural support for the other media in thecoalescer. In a sub-embodiment, one or more layers of media with thehydrophilic surface properties in the at least one coalescer comprise ametal.

In one embodiment, the multiple layers of media additionally comprise ahydrophilic media comprising a metal

Examples of hydrophilic media having the hydrophilic surface propertiesinclude high alloy metals such as stainless steel, high nickel alloys,and titanium alloys. Stainless steel is a steel alloy with a minimum of10.5% chromium content by mass. Stainless steel does not readilycorrode, rust or stain with water as ordinary steel does. There aredifferent grades and surface finishes of stainless steel to suit theenvironment the alloy must endure. Stainless steel can be used whereboth the properties of steel and corrosion resistance are desired.

Different metals and metal alloys are defined by their elementalcomposition. They can be defined by ASTM standards or by the unifiednumbering system. The unified numbering system (UNS) is an alloydesignation system widely accepted in North America. It consists of aprefix letter and five digits designating a material composition. Forexample, a prefix of S indicates stainless steel alloys, C indicatescopper, brass, or bronze alloys, N indicates nickel and nickel alloys, Rindicates refractory alloys, T indicates tool steels, and so on. Thefirst 3 digits often match older 3-digit numbering systems, while thelast 2 digits indicate more modern variations. ASTM E527-12 is theStandard Practice for Numbering Metals and Alloys in the UnifiedNumbering System (UNS). The UNS is managed jointly by the ASTMInternational and SAE International. A UNS number alone does notconstitute a full material specification because it establishes norequirements for material properties, heat treatment, form, or quality.

High alloy metals can include one or more of the following UNS numbers:N08020, S30403, S31603, S31703, N08904, 531254, N08367, N08225, S44660,S31803, S32205, S32750, N04400, N10276, N06022, N10665, R50400, R52400,R53400, and R52402.

In one embodiment, the high alloy metal is one that is especially costeffective as well as resistant to corrosion in the presence of thecoalesced droplets of the dispersed ionic liquid. One example of asuitable high alloy metal comprises: from 15.1 to 49 wt % nickel, from2.3 to 10 wt % molybdenum, from 0.00 to 2.95 wt % copper, and from 20 to59 wt % iron; wherein the metal alloy exhibits a corrosion rate lessthan 0.07 mm/year when performing the coalescing. These metal alloys aredescribed in US20160067668A1. In one embodiment, the high alloy metalhas a UNS number selected from the group consisting of N08904, S31254,N08367, and N08225.

In one embodiment, the multiple layers of media comprise a hydrophobicmedia having the fine pore size of 10 microns or less that coalescesdroplets in the emulsion and produces a clean liquid hydrocarbon stream.In one embodiment, the multiple layers of media comprise a hydrophobicmedia, and the hydrophobic media has the fine pore size of 20 microns orless, such as 1 to 10 microns. The hydrophobic media efficientlycoalesces droplets in the emulsion and produces the clean hydrocarbonstream. In one embodiment, the hydrophobic media has the fine pore sizeof 10 microns or less.

In one embodiment, the clean hydrocarbon stream is visually crystalclear when optically observed without any magnification. In oneembodiment, the clean hydrocarbon stream can have excellent lowturbidity, such as from 0.1 to less than 10 NTU, or from 0.1 to lessthan 5 NTU. In one embodiment, the clean hydrocarbon stream comprisesless than 50 ppmv of the dispersed ionic liquid, such as from zero to 20ppmv. The amount of the dispersed ionic liquid in the clean hydrocarbonstream can be measured by chemical analysis.

Examples of hydrophobic media having hydrophobic surface propertiesinclude materials made from hydrocarbons, including engineered polymers.Examples of engineered polymers include fiberglass, epoxy resins,polyester resins, vinylesters, thermoplastic resins, acrylic/phenolicresin, nylon, or combinations thereof. In one embodiment, the mediahaving hydrophobic surface properties comprise a fiberglass. In oneembodiment, the media having hydrophobic surface properties comprises apolyester material. Other examples of engineered polymers includepolybutylene terephthalate (PBT), polyamide materials, fluoropolymer,polyolefin or a media obtained by treating a fibrous engineered polymerwith an agent comprising fluorine functionalities.

In one embodiment, the multiple layers of media comprises at least onelayer of media material that remains relatively non-wettable by theretained ionic liquid droplets in the effluent from the pre-coalescer.Engineered polymers, such as those described previously can remainrelatively non-wettable by the retained ionic liquid droplets in theeffluent from the pre-coalescer.

In one embodiment, the coalescer is made without any metals.

In one embodiment, the media having hydrophobic surface propertiescomprises a fiberglass. The glass fibers in the fiberglass may berandomly arranged, flattened into a sheet (called a chopped strand mat),or woven into a fabric. A plastic matrix of the fiberglass may be athermosetting plastic, such as epoxy, polyester resin, vinylester, orother thermoplastic.

In one embodiment, the glass fibers in the fiberglass can be made ofvarious types of glass. In one embodiment, the glass fibers in thefiberglass comprise silica or silicate, with varying amounts of oxidesof one or more of calcium, magnesium, or boron. Fiberglass can be astrong lightweight material. Although it is not as strong and stiff ascomposites based on carbon fiber, it is less brittle, and its rawmaterials are much cheaper. In one embodiment, the bulk strength andweight of the fiberglass is better than many metals, and it can be morereadily molded into complex shapes and provide excellent structuralsupport for the coalescer.

In one embodiment, the integrated coalescing system comprises two ormore coalescers that are fluidly connected to the at least onepre-coalescer. In a sub-embodiment, the two or more coalescers can bearranged in a lead-lag configuration. The lead-lag configuration allowscontinuous operation when one of the coalescers is serviced or replaced.A lead-lag configuration of the coalescers, when used, ensures superiorperformance of the integrated system in separating the dispersed ionicliquid from the liquid hydrocarbon, even when there are defects in anyone of the coalescers. A lead-lag configuration of the coalescers alsohelps to extend the life of coalescer cartridges comprising the one ormore layers of media. A lead-lag configuration of two coalescers in theintegrated coalescing system is shown in FIG. 7.

EXAMPLES Example 1: Ionic Liquid Droplet Size Distribution inHydrocarbon-Ionic Liquid Emulsion with 10 Vol % of Ionic Liquid

In a cold flow unit, a mixture of ionic liquid and heptane wascirculated through a Venturi nozzle by a circulation gear pump underambient temperature and pressure producing an ionic liquid-heptaneemulsion. The mixture contained about 10 vol % of ionic liquid and 90vol % of heptane. The flow rate through the circulation pump was 2 GPM(0.454 m³/hr) and the pressure drop across the nozzle was 25 psi (172kPa). Under these conditions, a stable ionic liquid-heptane emulsion wasproduced, which, if left alone, could take greater than 8-12 hours toseparate naturally by gravity into a crystal clear layer of a heptanephase on the top and an ionic liquid phase on the bottom.

To accurately quantify the droplet size distribution of this ionicliquid-heptane emulsion in this cold flow unit, a Focused BeamReflectance Measurement (FBRM) probe manufactured by Mettler-Toledo wasused. As shown on FIG. 1, the probe was installed at a 45° angle withthe top measuring window inserted beneath the Venturi nozzle.

The ionic liquid droplet size distribution, expressed as number percentconcentration versus droplet size, was measured by the FBRM probe asconfigured in FIG. 1. FIG. 2 shows the ionic liquid droplet sizedistribution measured by the FBRM probe on the stable ionicliquid-heptane emulsion comprising 10 vol % ionic liquid. As can beseen, there is a wide range of ionic liquid droplets sizes ranging fromsmall sub-micron droplets to large droplets that are greater than 500microns.

Example 2: Ionic Liquid Droplet Size Distribution in Hydrocarbon-IonicLiquid Emulsion with 1 Vol % of Ionic Liquid

In the same cold flow unit as described in Example 1, a mixturecontaining 1 vol % ionic liquid and 99 vol % of heptane was emulsifiedby circulating the mixture through the Venturi nozzle. The cold flowunit was operated at a pump flow rate of 2 GPM (0.454 m³/hr), and thepressure drop across the Venturi nozzle was 11 psi (76 kPa). When thecold flow unit operation reached a steady state, the ionic liquiddroplet size distribution in the emulsion was measured by the FBRMprobe. FIG. 3 shows the ionic liquid droplet size distribution that wasmeasured by the FBRM probe on the stable ionic liquid-heptane emulsioncomprising 1 vol % ionic liquid. Comparing the droplet size distributionto the results obtained in Example 1, it can be seen that while theoverall shape of the droplet size distribution was appreciablydifferent, the distribution still clearly showed a wide range of ionicliquid droplet sizes, again ranging from small sub-micron droplets tolarge droplets that are greater than 500 microns.

Example 3: Polyamide-Stainless Steel Coalescer for Hydrocarbon-IonicLiquid Emulsion Separation (Comparative)

A slightly different cold flow unit was designed and tested. The designof this cold flow unit is shown in FIG. 4. This cold flow unit includeda pre-coalescer that was a filter and used also included a coalescerwith a cartridge made of multiple alternating layers of media includingpolyamide fabric and stainless steel mesh. This cold flow unit wastested to assess its ability to separate the emulsion produced earlierin Example 2. As shown in FIG. 4, the ionic liquid-heptane emulsionproduced by the Venturi nozzle was first introduced to a pre-coalescerhaving a filter with a filter pore size of 10 microns and then passed toa vertically oriented coalescer. The polyamide fabric used in thecoalescer had a relatively large pore size, estimated to be greater than100 microns. In the coalescer, as ionic liquid droplets passed throughthe coalescer cartridge's multiple layer media, they coalesced to formlarger droplets and settled down on the bottom of the coalescer. Afterseparation, the ionic liquid phase on the bottom of the coalescer andthe heptane phase on the top of the coalescer were circulated back tothe pump forming a circulation loop.

This cold flow unit was operated at a circulation pump flow rate of 2GPM (0.454 m³/hr) using a mixture of 1 vol % ionic liquid and 99 vol %heptane and the ionic liquid droplet size distribution in the emulsionproduced by the Venturi nozzle was measured by the FBRM probe. The sameionic liquid droplet size distribution that was measured by the FBRMprobe on the stable ionic liquid-heptane emulsion comprising 1 vol %ionic liquid described in Example 2 (and shown in FIG. 3) was obtained.The performance of this cold flow unit for producing a clean hydrocarbonstream was then carefully examined by visually observing, without anymagnification, the clarity of the heptane phase on the top of thecoalescer. After reaching a steady state, the heptane phase remainedhazy, indicating that there were still appreciable amounts ofunseparated fine ionic liquid droplets remaining in the heptane phase.This cold flow unit, therefore, was not able to completely separate theionic liquid droplets from the emulsion produced by the Venturi nozzle.

Example 4: Fiberglass-Stainless Steel Coalescer for Hydrocarbon-IonicLiquid Emulsion Separation, with a Pre-Coalescer

Another alternate cold flow unit, as shown in FIG. 5, comprised apre-coalescer that was a filter, and a coalescer having a coalescercartridge made of multiple layers of media including a fiberglass fabricand stainless steel mesh. The filter in the pre-coalescer had a filterpore size of 10 microns. The coalescer in this cold flow unit wasoriented horizontally. This cold flow unit was tested to separate theemulsion produced in Example 2. In this coalescer cartridge, thefiberglass media was a tightly meshed fabric with a fine pore size inthe range of 10 micron.

This cold flow unit was tested to assess its ability to separate theemulsion produced earlier in Example 2. As shown in FIG. 5, the ionicliquid-heptane emulsion produced by the Venturi nozzle was firstintroduced to a pre-coalescer having a filter with a filter pore size of10 microns and then passed to the horizontally oriented coalescer. Inthe coalescer, as ionic liquid droplets passed through the coalescercartridge's multiple layer media, they coalesced to form larger dropletsand settled down on the bottom of the coalescer. After separation,similar to Example 3, the ionic liquid phase on the bottom of thecoalescer and the heptane phase on the top of the coalescer werecirculated back to the pump forming a circulation loop.

This cold flow unit was operated at a circulation pump flow rate of 2GPM (0.454 m³/hr) using a mixture of 1 vol % ionic liquid and 99 vol %heptane and the ionic liquid droplet size distribution in the emulsionproduced by the Venturi nozzle was measured by the FBRM probe. The sameionic liquid droplet size distribution that was measured by the FBRMprobe on the stable ionic liquid-heptane emulsion comprising 1 vol %ionic liquid described in Example 2 (and shown in FIG. 3) was obtained.The performance of this cold flow unit for producing a clean hydrocarbonstream was then carefully examined by visually observing, without anymagnification, the clarity of the heptane phase on the top of thecoalescer. After reaching a steady state, the heptane phase was crystalclear, with a turbidity of 2.8 NTU, indicating that there wasessentially complete separation of the ionic liquid droplets from theemulsion. The amount of ionic liquid remaining in the separated heptanewas measured by chemical analysis to be less than 20 ppmv.

Example 5: Fiberglass-Stainless Steel Coalescer for Hydrocarbon-IonicLiquid Emulsion Separation, without a Pre-Coalescer (Comparative)

To test the impact of the pre-coalescer filter on the separationperformance of the cold flow unit, the cold flow testing unit andprocess described in Example 4 was repeated, but this time, with thepre-coalescer filter bypassed. As in Example 4, the same ionic liquiddroplet size distribution that was measured by the FBRM probe on thestable ionic liquid-heptane emulsion comprising 1 vol % ionic liquiddescribed in Example 2 (and shown in FIG. 3) was obtained. Afterreaching a steady state, the heptane was hazy, with a turbidity of 11.6,indicating unsatisfactory separation of the ionic liquid from theemulsion. The amount of ionic liquid remaining in the separated heptanein this comparative example was measured to be 40 ppmv by chemicalanalysis.

Example 6: Integrated Coalescing System with Bulk Settler,Pre-Coalescer, and Fiberglass-Stainless Steel Coalescer forHydrocarbon-Ionic Liquid Emulsion Separation

A pilot plant unit designed for producing alkylate gasoline was used forthis example. The pilot plant unit was configured to produce a reactoreffluent comprising an emulsion having a dispersed ionic liquid with awide range of droplet sizes ranging from small droplets less than 20microns to large droplets greater than 500 microns, with the dropletsize distribution being similar to those shown in FIGS. 2 and 3. Thispilot plant unit included an integrated coalescing system comprising abulk settler, a pre-coalescer, and a coalescer. FIG. 6 shows asimplified schematic diagram of this pilot plant unit with theintegrated coalescing system. In this pilot plant unit, a reactantmixture containing light hydrocarbon and 2-5 vol % of ionic liquid wascirculated around a reactor loop consisted of a Venturi nozzle, analkylation reactor vessel, a circulation pump, and a heat exchanger. Astable hydrocarbon-ionic liquid emulsion formed in the alkylationreactor, and this emulsion was highly effective at performing thedesired alkylation reaction. The reactor effluent remained a stablehydrocarbon-ionic liquid emulsion.

To separate the ionic liquid from the hydrocarbon-ionic liquid emulsion,the reactor effluent was first introduced to a bulk settler containing acoarse coalescing pad that allowed over 90 vol % of large ionic liquiddroplets to settle down by gravity. The residence time in the bulksettler was less than 10 minutes. The settling was done effectively inthis bulk settler with the coarse coalescing pad using gravity, and thesettling produced a clean ionic liquid stream essentially free ofhydrocarbon and a raw hydrocarbon stream. The raw hydrocarbon phase fromthis settler still contained a substantial amount of the ionic liquid,entrained as droplets. The raw hydrocarbon stream was a separated liquidhydrocarbon phase comprising retained ionic liquid droplets. Thisseparated liquid hydrocarbon phase from the settler was then introducedto a pre-coalescer comprising a fiberglass-based filter with a filterpore size of 6-10 micron. This pre-coalescer removed solid particulatesthat could havefouled the downstream coalescer. This pre-coalescer alsofunctioned as a preconditioner that enabled much more efficientseparation in the downstream coalescer. The effluent from thepre-coalescer flowed directly to the coalescer.

In the coalescer in this pilot plant unit, the coalescer cartridgecontained multiple alternating layers of tight fiberglass media, in theform of fabrics having fine pore sizes around 10 micron, and stainlesssteel mesh. The coalescer was highly effective at completely separatingessentially all of the ionic liquid droplets from the hydrocarbon phase.The obtained clean hydrocarbon stream was then sent to a series ofdistillation columns for further separation, while the ionic liquidstreams recovered from the emulsion from both the bulk settler and thecoalescer were sent to and collected in an ionic liquid reservoir beforethe ionic liquid in the reservoir was recycled back to the reactor.

The clean ionic liquid phases that were separated in both the bulksettler and the coalescer were sent to an ionic liquid reservoir andcirculated back to the alkylation reactor vessel. No observable solidparticles formed in any of the clean ionic liquid streams or the cleanhydrocarbon stream in this pilot plant unit.

This pilot plant unit with the integrated coalescing system successfullyproduced crystal clear hydrocarbon effluent from the top of thecoalescer and achieved reliable operation for an extended period. Thisintegrated coalescing system would be expected to operate reliably overseveral years. The amount of the ionic liquid remaining in the cleanhydrocarbon stream, which was sent to the series of distillationcolumns, was estimated to be from zero to 10 ppmv during the entireoperation of this pilot plant unit, once it reached a steady state.

The transitional term “comprising”, which is synonymous with“including,” “containing,” or “characterized by,” is inclusive oropen-ended and does not exclude additional, unrecited elements or methodsteps. The transitional phrase “consisting of” excludes any element,step, or ingredient not specified in the claim. The transitional phrase“consisting essentially of” limits the scope of a claim to the specifiedmaterials or steps “and those that do not materially affect the basicand novel characteristic(s)” of the claimed invention.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Furthermore, all ranges disclosed herein are inclusive ofthe endpoints and are independently combinable. Whenever a numericalrange with a lower limit and an upper limit are disclosed, any numberfalling within the range is also specifically disclosed. Unlessotherwise specified, all percentages are in weight percent.

Any term, abbreviation or shorthand not defined is understood to havethe ordinary meaning used by a person skilled in the art at the time theapplication is filed. The singular forms “a,” “an,” and “the,” includeplural references unless expressly and unequivocally limited to oneinstance.

All of the publications, patents and patent applications cited in thisapplication are herein incorporated by reference in their entirety tothe same extent as if the disclosure of each individual publication,patent application or patent was specifically and individually indicatedto be incorporated by reference in its entirety.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. Many modifications of the exemplaryembodiments of the invention disclosed above will readily occur to thoseskilled in the art. Accordingly, the invention is to be construed asincluding all structure and methods that fall within the scope of theappended claims. Unless otherwise specified, the recitation of a genusof elements, materials or other components, from which an individualcomponent or mixture of components can be selected, is intended toinclude all possible sub-generic combinations of the listed componentsand mixtures thereof.

The invention illustratively disclosed herein suitably may be practicedin the absence of any element which is not specifically disclosedherein.

It is claimed:
 1. A process for separating an ionic liquid from a liquidhydrocarbon, comprising: a. settling an emulsion of the ionic liquid andthe liquid hydrocarbon, wherein the emulsion comprises a dispersed ionicliquid with a wide range of droplet sizes, ranging from small dropletsless than 20 microns to large droplets greater than 500 microns, toseparate a clean ionic liquid phase that is free of the liquidhydrocarbon from a separated liquid hydrocarbon phase comprisingretained ionic liquid droplets; b. pre-coalescing the separated liquidhydrocarbon phase in at least one pre-coalescer that removes anyparticles and begins to form coalesced droplets of the dispersed ionicliquid; c. coalescing an effluent from the at least one pre-coalescer inat least one coalescer comprising multiple layers of media having a finepore size of 20 microns or less to produce a clean hydrocarbon streamthat is essentially free of the dispersed ionic liquid and producesadditional amounts of the clean ionic liquid phase.
 2. The process ofclaim 1, wherein the emulsion comprises the small droplets of the ionicliquid that are less than 10 microns in size.
 3. The process of claim 1,wherein the at least one pre-coalescer has a medium with a pore sizefrom 1 to 25 microns.
 4. The process of claim 1, wherein the multiplelayers of media are arranged to have alternating hydrophilic surfaceproperties and hydrophobic surface properties.
 5. The process of claim1, wherein the multiple layers of media comprise a hydrophobic mediacomprising an engineered polymer.
 6. The process of claim 5, wherein themultiple layers of media additionally comprise a hydrophilic mediacomprising a metal.
 7. The process of claim 6, wherein the metal is ahigh alloy metal.
 8. The process of claim 1, wherein the multiple layersof media comprise a hydrophobic media having the fine pore size of 10microns or less that coalesces droplets in the emulsion and produces theclean hydrocarbon stream.
 9. The process of claim 1, additionallycomprising feeding the clean ionic liquid phase to an inlet of ahydrocarbon conversion reactor.
 10. The process of claim 1, wherein thesettling is done in at least one bulk settler using gravity.
 11. Theprocess of claim 10, wherein the emulsion remains in the at least onebulk settler for 0.10 to 10 hours.
 12. The process of claim 1, whereinthe clean ionic liquid phase contains a majority of an introduced ionicliquid that is fed to a hydrocarbon conversion reactor that produces theemulsion.
 13. The process of claim 1, wherein the clean hydrocarbonstream comprises from zero to 20 ppmv of the dispersed ionic liquid. 14.The process of claim 1, wherein the clean hydrocarbon stream has aturbidity from 0.1 to less than 5 NTU.